At a Glance

Why Get Tested?

When to Get Tested?

When your doctor suspects that you have certain cancers of the liver, testes, or ovaries; at intervals during and after treatment for one of these cancers; sometimes when you have chronic hepatitis or cirrhosis

Sample Required?

A blood sample drawn from a vein in the arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

This test measures alpha-fetoprotein (AFP) in the blood. AFP is a protein produced primarily by fetal liver and the portion of a developing embryo that is similar to the yolk cavity in bird eggs (yolk sac tissues). AFP concentrations are typically elevated when a baby is born and then decline rapidly. In healthy children and non-pregnant adults, AFP is normally only detectable at very low levels.

Liver damage and certain cancers can increase AFP concentrations significantly. AFP is produced whenever liver cells are regenerating. With chronic liver diseases, such as hepatitis and cirrhosis, AFP may be chronically elevated. Very high concentrations of AFP may be produced by certain tumors. This characteristic makes the AFP test useful as a tumor marker. Increased amounts of AFP are found in many people with a type of liver cancer called hepatocellular carcinoma and in a liver cancer occurring in infants called hepatoblastoma. They are also found in some people with cancers of the testes and ovaries.

AFP exists in several different variants. Traditionally, when a doctor orders an AFP test, it is for a total AFP, one that measures all of the AFP variants together. This is the primary AFP test in the United States.

One of the variants is called L3 because of its ability, in the laboratory, to bind to a particular protein called Lens culinaris agglutinin. The AFP-L3% test is a relatively new test that compares the amount of AFP-L3 to the total amount of AFP. An increase in the percentage of L3 is associated with increased risk of developing hepatocellular carcinoma in the near future and of having a poorer prognosis, as the L3-related cancers tend to be more aggressive. The AFP-L3% test is being ordered by a few doctors in the U.S. and is in wider use in some other countries, such as Japan.

Is any test preparation needed to ensure the quality of the sample?

The Test

How is it used?

AFP is used as a tumor marker to help detect and diagnose cancers of the liver, testes, and ovaries. Though the test is often ordered to monitor people with chronicliver diseases such as cirrhosis, chronic hepatitis B or hepatitis C because they have an increased lifetime risk of developing liver cancer, most current guidelines do not recommend this use. A doctor may order an AFP test, along with imaging studies, to try to detect liver cancer when it is in its earliest and most treatable stages.

If a person has been diagnosed with hepatocellular carcinoma or another form of AFP-producing cancer, an AFP test may be ordered periodically to help monitor the person's response to therapy and to monitor for cancer recurrence.

An AFP-L3% is sometimes also ordered to compare the amount of the AFP variant called AFP-L3 to the total amount of AFP. The AFP-L3% test is not yet widely used in the U.S. but has gained wider acceptance in other countries such as Japan. The test is used to help evaluate the risk of developing hepatocellular carcinoma, especially in those with chronic liver disease, and also to evaluate response of hepatocellular carcinoma to treatment.

When is it ordered?

A physician may order an AFP blood test when:

It is suspected that someone has liver cancer or certain cancers of the testes or ovaries; cancer may be suspected when, for example, lumps are felt in the abdominal area during a physical exam or when imaging tests detect possible tumors.

Someone who has been diagnosed with and treated for a cancer of the liver, testes, or ovaries is being monitored for the effectiveness of treatment

Someone is being monitored for cancer recurrence

An AFP-L3% is sometimes ordered to help evaluate the risk of hepatocellular carcinoma when a person has chronicliver disease or to test the effectiveness of treatment of of hepatocellular carcinoma or monitor for its recurrence.

What does the test result mean?

Increased AFP levels may indicate the presence of cancer, most commonly liver cancer, cancer of the ovary, or germ cell tumor of the testes. However, not every liver, ovarian, or testicular cancer will produce significant quantities of AFP. Elevated levels may sometimes be seen with other cancers such as stomach, colon, lung, breast, and lymphoma, although it is rarely ordered to evaluate these conditions. Other diseases such as cirrhosis and hepatitis can also cause increased levels.

When AFP is used as a monitoring tool, decreasing levels indicate a response to treatment. If concentrations after cancer treatment do not significantly decrease, usually to normal or near normal levels, then some of the tumor tissue may still be present. If concentrations begin to increase, then it is likely that the cancer is recurring. However, since AFP can be increased in hepatitis or cirrhosis, AFP levels can sometimes be misleading. If AFP levels are not elevated prior to treatment, then the test will not generally be useful to monitor the effectiveness of treatment or to monitor for recurrence.

When the AFP concentrations of people with chronic liver disease go from moderately elevated to greatly elevated, their risk of developing liver cancer increases. When total AFP and AFP-L3% are significantly elevated, then the affected person has an increased risk of having or developing hepatocellular carcinoma in the next year or two. However, both AFP and AFP-L3% concentrations can be elevated, and fluctuate, in people with chronic hepatitis and cirrhosis. In these cases, a sharp increase in AFP is more important than the actual numerical value of the test result.

Is there anything else I should know?

Not every person with increased AFP and AFP-L3% test results has cancer or will develop liver cancer. The AFP and AFP-L3% tests are not diagnostic; they are indicators. They must be used in conjunction with information from a history and physical examination as well as imaging studies to look for the development of tumors. Although these tests can provide useful information, they are not as specific or sensitive as doctors would wish. AFP can temporarily increase whenever the liver is injured and regenerating, and moderate elevations can be seen with a variety of conditions. Because of this, AFP testing can give some false positives. In addition, not every cancer will produce AFP, so a person could still have cancer even when the AFP is normal. For these reasons, the AFP test should not be used to screen the general population for cancer.

AFP is not only a tumor marker. Because AFP is produced by the fetus, levels are normally higher in pregnant women and in their newborns. For more information on AFP testing during pregnancy, see Triple or Quad Screen.

Common Questions

1. What are the risk factors for hepatocellular carcinoma?

This cancer usually occurs in people who have chronic scarring of the liver, called cirrhosis. Most commonly, this is caused by chronic infection from one of two viruses: hepatitis B and hepatitis C. Alcohol abuse also increases the risk of developing cirrhosis. Some inherited diseases, especially a disorder called hemochromatosis (in which the body absorbs too much iron), can cause cirrhosis and, in time, hepatocellular carcinoma, as can non-alcoholic steatohepatitis (NASH).

2. If my AFP is abnormal, do I need other tests?

If you have chronic liver infection or damage and your AFP suddenly rises, or if it is very elevated, your doctor will usually ask for a study to look at your liver, such as an ultrasound exam, a CT scan, or an MRI scan. These scans can usually spot liver cancers if they are present. Your doctor may also order a blood test for des-gamma carboxy prothrombin (DCP) to help detect liver cancer.

Article Sources

NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.

Sources Used in Current Review

(Revised 2012 October 5). Ovarian Cancer. American Cancer Society [On-line information]. Available online at http://www.cancer.org/cancer/ovariancancer/detailedguide/index through http://www.cancer.org. Accessed October 2012.

(December 2011) Llovet J, et al. Clinical Practice Guidelines: Management of hepatocellular carcinoma. European Association for the Study of the Liver and European Organisation for Research and Treatment of Cancer. Journal of Hepatology 2012 vol. 56 j 908–943. PDF available for download at http://www.easl.eu/assets/application/files/d38c7689f123edf_file.pdf through http://www.easl.eu. Accessed November 2012.

(Revised 2008 December 08). Tumor Markers, What are tumor markers? American Cancer Society [On-line information]. Available online at http://www.cancer.org/docroot/PED/content/PED_2_3X_Tumor_Markers.asp?sitearea=PED through http://www.cancer.org. Accessed May 2009.

Walzer, N. and Kulik, L. (2008 June 10). Hepatocellular Carcinoma: Latest Developments. Medscape from Current Opinion in Gastroenterology [On-line information]. Available online at http://www.medscape.com/viewarticle/573576 through http://www.medscape.com. Accessed May 2009.

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This article was last reviewed on December 3, 2012. | This article was last modified on February 24, 2015.

The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.

The modified date indicates that one or more changes were made to the article. Such changes may or may not result from a full review of the article, so the two dates may not always agree.